The cardio required for biking is top notch. Fill those tires up then keep the rubber side down while doing hills for a few hours!
There is a saying that if you can run 2 miles you can run 26 miles.
40 minutes is a fairly decent pace and while you would need to keep a 6 minute mile pace, you'd need to run each mile at a 6 minute pace. Also, there is something called the runners high. I get that around the 3.5 mile mark and then my pace picks up as the body settles into the rhythm. Find out how long it is until you reach that runners high.
Always stretch, both before and after. And, hydrate often. Stop drinking caffeinated drinks and alcoholic drinks as those will dehydrate you. (Yes, I know it is hard to give up alcohol for some, but some sacrifices must be made for optimum performance). Also, what is your diet like? Fatty foods and lots of pasta? Trade that off for brown rice, salmon, or tuna with veggies. Sushi is an excellent replacement. Nigiri is another great replacement and probably preferred as it eliminates the not-as-healthy sauces.
Oh, do squats as well to strengthen your thighs. The quadriceps is the largest muscle group in the body and when it is broken down, the body secretes naturally produced human growth hormone to make the muscles stronger. But with the quads, as it is so large, there is an abundance of HGH and your other muscles will benefit/grow.
(I've been competing in extreme sports since I was 13 and served 5 years in the Marines. If you have questions on training routines, don't hesitate to shoot me a PM.)